1. Field of the Invention
For supplying fuel to combustion chambers of internal combustion engines, injection systems for injecting fuel are used whose injectors are exposed to extremely high pressures. In order not to impair the efficiency of such fuel injectors, it is absolutely necessary to assure replicable injector performance. Suitable injectors as a rule have an electromagnetic valve, and an armature stroke of such an electromagnetic valve must be adjusted precisely when applicable injectors are being installed, since the injector dynamics are definitively affected by the armature stroke. For instance, given a fixed triggering duration of a magnet coil of the electromagnetic valve, the injected fuel quantity is dependent on the armature stroke.
2. Description of the Prior Art
In currently known electromagnetic valves used in conjunction with injectors in injection systems for fuel supply purposes, the armature stroke is adjusted via adjusting rings, which fix the axial position of a corresponding armature stop. Via the armature, or the motion of the armature in the axial direction and its axial (terminal) position, the opening of a nozzle of the injector and thus the injected fuel quantity are defined. When an electromagnetic valve or an injector is assembled, the components that determine the armature stroke are measured, and on the basis of the measurement results, the dimensions, required for a certain predetermined armature stroke, of a adjusting ring are attained. A magnet group, together with the adjusting ring dimensioned in accordance with the calculation, is then screwed to the injector body, and then the armature stroke is measured in the screwed-together or in other words tightened state. For use in extremely high-pressure injection system injectors, however, acceptable tolerances for the armature stroke are in the micrometer range, if replicable injector performance is to be assured. Because of the only slight deviations in tolerances allowed, after an initial installation as described above the armature stroke does not always remain within the tolerance values. To assure the adjusting of the armature stroke within the close tolerance values then, the magnet group must be completely removed, and the armature stroke must be reset by way of the choice of an adjusting ring of a different size. Possibly this operation may even have to be repeated more than once, until acceptable adherence to tolerances of the armature stroke can be attained. This process leads to high costs in production.
In view of the stringent requirements for accuracy in adjusting the armature stroke of electromagnetic valves, especially for used in conjunction with injectors in injection systems for injecting fuel into combustion chambers of internal combustion engines, it is desirable and necessary to assure the accuracy of the adjustment of the armature stroke without additional installation requirements.
The present invention has the object in particular of furnishing a device for adjusting an armature stroke of an armature of an electromagnetic valve, in particular for use in conjunction with injectors in injection systems, by which even after an initial installation, because it is possible to adjust the armature stroke, dismantling again if the armature stroke is adjusted incorrectly is unnecessary, and as a result the production costs can be reduced. An improved tolerance position of the armature stroke moreover makes a more-precise output of a fuel quantity from a suitably equipped injector.